Negative electrode and process of making the same.



UNITED STATES PATENT onnron.

WIB'J. TASSIN, OF WASHINGTON, DISTRICT OF COLUMBIA.

NEGATIVE ELECTRODE AND PROCESS OF MAKING THE SAME.

No Drawing.

To all whom it may concern Be it known that I, WIRT TASBIN, a citizen of the United States, residing at Washington, in the District of Columbia, have invented .certain new and useful Improvements in Negative Electrodes and Processes of Making the Same, of which the following is a specification.

This invention relates to negative electrodes and processes of making the same; and it comprises a rocess of making highly eflicient and durab e negative electrodes for primary cells of a type analogous to the Lalande type, wherein an intimate mixture of cuprous and cupric oxids in the approximate ratio of 2: 1 is prepared, advantageously by calcining copper sulfate at about 1500 F. to remove sulfuric acid, and then bringing the calcined iron-free material to a temperature at which oxygen is liberated and the material is at a fusion temperature, or around 1925 F., and forming the intimate mixture of cuprous and cupric oxids thus produced into an electrode of a desired shape; and it further comprises asa new article of manufacture an oxid electrode composed of cuprous and cupric oxids in a state of intimate mixture, this intimate admixture existing in the particles or grains of which the electrode is composed and the admixture being advantageously so intimate as to give the material practically the characters of a chemical compound, and-in the approximate ratio of 2:1, the particles of the electrode advantageously having the characteristics of fused or sintered material; all as more fully hereinafter described and as claimed.

In the common type of the Lalande cell, the electrodes are respectively composed of black copper oxid or cupric oxid, and zinc, the electrolyte being, usually, alkaline in its nature. The electrolyte may or may not be thickened with variousmaterials to 've the so-called dry cell. In this cell t e elec-- a binder ofsome sort and heated to a. .tem-

pei-ature sufiicient toconvert it, with theaid Specification 'of Letters Patent.

tion isusually I 'ness, is indefinite and unsatisfactory. In an Patented Feb. 23, 1915.

Application filed June 6, 1914. Serial No. 843,495.

of the binder, into a coherent but porous gards this type of primary cell I have found that a longer life under load conditions with a greater recuperative power and other advantages are obtained by using an electrode composed ofa homogeneous mixture or compound of the red or cuprous oxid with a less quantity of the black oxid. The proportion of cuprous oxid to cupric oxid may be, and

very advantageously is, as high as 2:1 although other ratios may beused. In an intimate and homogeneous mixture of the two oxids any proportion of cuprous oxid is advantageous but by far the best results are given by a high proportion, such as the 2: 1 ratio. The ratio in an otherwise desirable electrode material may be easily secured by a method hereinafter set forth. The electrode material is best substantially free of iron. Cells provided with electrodes of this and the full discharge rate is reached immediately on placing into action, something which is not true of the usualblack oxid electrode. The recuperative power is greater than that. of the ordinary black oxid elec-v trode.

While a negative electrode of the ordinary black copper oxid type after exhaustion may in part be restored by a reversal of the electric current through the cell,-such restoraincomplete, lacks posit veelectrode of my type on the other hand a reversal of the current. efiiciently restoresthe exhausted electrode and rapidly gives definite and positive results which are superior to those obtained from such ordinary copper-oxid electrodes so treated.

While my cupro-cupric electrode may be i made of very finely powdered oxids obtained in other ways and intimately admixed in the correct proportion, I find that can d1- 'rectly prepare the electrode materlal from copper salts, even the crude commercial salts, 7

simple ways. For example in so can take copper sulfate (cupric sulwhich may be of a low grade commeza fin ver 01 g ml cially, and heat it in any usual type of.fur-' nace to about 1500 F. This heating 'calcines the salt, removing the sulfuric acid and converts any iron sulfate which may be present into iron oxid,-which, under these conditions is of the magnetic type. The operation gives me a material containing all the iron oxid so prepared and finegrind' it, advantageously to about 100 mesh, and treat with a magnet. In the case of pure copper sulfate this step of removing iron is not necessary and fine grinding, etc., after calcining may be omitted, the heating being continued and increased to perform the next or deoxidizing step without cooling down. The fine ground treated material is next brought to a temperature at which the copper oxid is parti ally deoxidized; to a heat at which it evolves oxygen freely. This temperature is about 1900"v F. I find that a temperature as near 1925 F. as possible is the best adapted for my purposes. Temperatures much above 1925 give a less desirable product. At 1900-1925 there is a great evolution of oxygen and the material finally becomes converted into the two oxids, the product being a homogeneous material in which they exist as a compound or composition in which mechanical separation is imposible. If not in a state of combination they are at all events so intimately mingled that the state of mixture isalmost, if not quite, molecular.

An equilibrium is established with a molecular ratio of Cu O :CuO=2 1. At the stated 1 temperature both oxids are fusible and a fused or s'intered'product results; the degree of fusion or sintering depending upon the time of exposure to the heat. Cuprous and cupric oxids otherwise produced may be fine ground, mixed and brought to this temperature with quite similar results. But, 1 find it much better to produce the two oxids by heating black oxid till evolution of oxygen and equilibrium result since the mixture of the two oxids is then better than :can be attained mechanically. However the material of the electrode of the present invention is prepared, to secure the results desired in this invention the two oxids of copper must be so intimately admixed as to give a sub:

- stantially homogeneous composition, not

only considering the electrode as a whole but also the several grains or particles of which it maybe composed; there must be visible no particles, lines or bodies of either oxid existing alone.

While thefused or sintered material may be simply granulated and used in porous bags or containers, I find it better'to useitv 1n molded form. In so doing I may simply take the calcined material first produced and'place it in a container or mold of the desired shape. and fuse or sinter it at a temfused material, fine grind. and then shape.

For this purpose I mix the fine ground material, which is advantageously ground to 100 mesh or finer, with a binder which may be a carbonaceous material such as molasses, glucose, etc. and mold by .any suitable apparatus into the desired shape. The molded article ma then be baked to set the binder. With carbonaceous materials the baking temperature may be around 350 F.; with silicate binders such as glass, waterglass, etc., or alkaline binders, such as soda, the bakin temperature is varied to suit conditions. regard the carbonaceous binders as being the more advantageous kind since the others will in a degree act as a diluent for the oxids; as a varnish or coating for the several granules and they, activity of the cell.

Prior to molding it is advantageous to insert a metal wire, preferably of copper, into the mass to provide for the necessary terminal. The electrode so produced may be used either in a primary or a secondary cell; but I regard it as particularly advantageous for primary cells.

What I claim is :v

1. As a new article of manufacture, an

to that extent, hinder the electrode composed of an intimate and unihaving the characteristics of fused material.

5. The process of manufacturing electrodes which comprises maintaining a copper oxid at about the fusing point till an equilibrium between cuprous and cupric oxids is established and then molding. into a desired form.

v6. In the manufacture of electrodes the process which comprises calcining a copper salt to remove acid constituents, heating the calcined material until fusion sets. in and a portion of the oxygen is evolved with-formation of: cuprous oxid, and molding into shape.

7 .The'process of making electrodes from impure copper sulfate containing iron which comprises calcining such copper sulfate to remove sulfuric acid and form magnetic oxid of iron, separating the magnetic om'd I of iron, heatingthe purified j naterial fusion sets in and a portion of the oxygen and cupric oxids is established in the apis evolved, and moldin into shape. proximate ratio 2 :1.

8. The process of ma g electrodes which In testimony whereof, I afiix my signature comprises calcining a copper salt and bring in the presence of two subscribing Witnesses.

ing the calcined material to a fusing tem- WIRT TASSIN. perature, heating at such temperature being Witnesses: maintained until a portion of the oxygen is K. P. MQELROY,

evolved and an equilibrium between cuprous J. H. Sreenns. 

